1. Calculation and Experimental Studies of Systems of Dibasic Carboxylic Acids and Properties of Eutectics
- Author
-
I. K. Garkushin, A. V. Kolyado, and S. M. Alenova
- Subjects
Materials science ,Dibasic acid ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Liquidus ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,chemistry ,Aluminium ,Differential thermal analysis ,Physical and Theoretical Chemistry ,Solubility ,0210 nano-technology ,Eutectic system ,Phase diagram - Abstract
The liquidus lines of binary systems of dibasic carboxylic acids HOOC–(CH2)n–COOH (n = 3, 4, 7, 8) and eutectic coordinates were calculated by the Schrӧder–Le Chatelier equation. The experimental studies were performed by differential thermal analysis on a DSC heat flux microcalorimeter. Five or six mixtures with different contents of components were studied in each system. The phase diagrams were constructed based on the set of DSC data. The experimental melting temperatures and the composition of binary eutectics were compared with the calculated values. All the systems were of the eutectic type. A theoretical analysis of the solubility of the acids was performed, and the equations of solubility of acids in water were obtained. The eutectic composition of the pentanedioic–hexanedioic acids system was chosen based on the analysis of the solubility data; it can be used to obtain anodic coatings on aluminum. For the eutectics of the system, the solubility in water was experimentally studied at temperatures from 20 to 60°C. The composition of electrolyte for aluminum anodization was developed: eutectic mixture of pentadioic and hexanedioic acids, ethanedioic acid, and water. The temperature and time of aluminum anodization were recommended.
- Published
- 2020